Read and Think!

Physicists expand the circle, philosophers help clear up the paradoxes

By Jim Holt

A KERFUFFLE has broken out between philosophy and physics. It began when philosopher David Albert gave a sharply negative review in The New York Times to a book by physicist Lawrence Krauss that purported to solve, by purely scientific means, the mystery of the universe's existence.

The physicist responded to the review by calling Dr Albert 'moronic', and argued that philosophy, unlike physics, makes no progress and is rather boring, if not totally useless. And then the kerfuffle was joined on both sides.

This is hardly the first occasion on which physicists have made disobliging comments about philosophy. Last year, at a Google Zeitgeist conference in England, Dr Stephen Hawking declared that philosophy was 'dead'. Another great physicist, Nobel laureate Steven Weinberg, has written that he finds philosophy 'murky and inconsequential' and of no value to him as a working scientist.

And physicist Richard Feynman, in his famous lectures on physics, complained that 'philosophers are always with us, struggling in the periphery to try to tell us something, but they never really understand the subtleties and depths of the problem'.

Why do physicists have to be so churlish towards philosophy? Philosophers, on the whole, have been much nicer about science. 'Philosophy consists in stopping when the torch of science fails us,' Voltaire wrote back in the 18th century. And in the last few decades, philosophers have come to see their enterprise as continuous with that of science.

It is noteworthy that the 'moronic' philosopher who kicked up the recent shindig by dismissing the physicist's book himself holds a PhD in theoretical physics.

Physicists say they do not need any help from philosophers. But sometimes physicists are, whether they realise it or not, actually engaging in philosophy themselves. And some of them do it quite well. Dr Weinberg, for instance, has written brilliantly on the limits of scientific explanation - which is, after all, a philosophical issue. It is also an issue on which contemporary philosophers have interesting things to say.

Dr Weinberg has attacked philosophical doctrines like positivism (science should concern itself only with things that can actually be observed). But it happens to be a mantle that Dr Hawking proudly wraps himself in; he has declared that he is 'a positivist who believes that physical theories are just mathematical models we construct, and that it is meaningless to ask if they correspond to reality'. Is Dr Hawking's positivism the same positivism that Dr Weinberg decries? That would be an issue for philosophical discussion.

Physicist Roger Penrose is a self-avowed Platonist, since he believes that mathematical ideas have an objective existence. The disagreement between Dr Hawking the positivist and Sir Roger the Platonist - a philosophical one - has hard scientific consequences: They take radically opposing views of what is going on when a quantum measurement is made. Is one of them guilty of philosophical naivete? Are they both?

Finally, consider the anti-philosophical strictures of Feynman. 'Cocktail party philosophers', he said in a lecture, think they can discover things about the world 'by brainwork' rather than experiment. But in another lecture, he announced that the most pregnant hypothesis in all of science is that 'all things are made of atoms'.

Who first came up with this hypothesis? The ancient philosophers Leucippus and Democritus. And they did not come up with it by doing experiments.

Today the world of physics is in many ways conceptually unsettled. Will physicists ever find an interpretation of quantum mechanics that makes sense? Is quantum entanglement logically consistent with special relativity? Is string theory empirically meaningful? How are time and entropy related? Can the constants of physics be explained by appealing to an unobservable 'multiverse'?

Philosophers have in recent decades produced sophisticated and illuminating work on all these questions. It would be a pity if physicists were to ignore it.

And what about the oft-heard claim that philosophy, unlike science, makes no progress? As philosopher Bertrand Russell (no slouch at physics and maths) observed, philosophy aims at knowledge, and as soon as it obtains definite knowledge in a specific area, that area ceases to be called 'philosophy'. Scientific progress gives philosophers more and more to do. Said Nietzsche: 'As the circle of science grows larger, it touches paradox at more places.'

Physicists expand the circle, philosophers help clear up the paradoxes. May both camps flourish.

NEW YORK TIMES

Jim Holt is the author of the forthcoming book, Why Does The World Exist? An Existential Detective Story.